The present invention relates to a hoist for a helicopter, or other aircraft capable of hovering in flight, which is for use in rescue operations, handling cargo, and the like, and deals more particularly with an improved hoist which is retractable to within the aircraft when not in use.
Hoists that are mounted on aircraft capable of hovering in flight, generally helicopters or vertical takeoff or landing aircraft (VTOLs), are known in the art, and exist in a variety of forms. The known aircraft hoists generally comprise a boom or truss extended from the side of the aircraft and a pulley located at the end of the boom and guiding a cable. The cable is driven by a hydraulically actuated winch. During a rescue mission, for example, the winch is actuated to pay out the cable over the end of the boom while the aircraft hovers over the person to be rescued. The person is held at the end of the cable and the pilot or other crew member actuates the winch to pull in the cable and carry the person toward the aircraft.
In most known hoists the boom is externally mounted from the side of the aircraft. The boom is generally located near the top of the aircraft cabin doorway so that when a person or an article is lifted it can be easily transferred from the cable extended from the end of the boom to within the cabin of the aircraft. One problem associated with known hoists having an externally mounted boom is that sometimes the aircraft's engine air intake port is located near the top of the cabin doorway and the boom then interferes with the engine inlet airflow. An additional problem associated with the externally mounted boom is that the boom adds aerodynamic drag to the aircraft, which has become of increased importance with high speed helicopters and VTOLs.
Some known hoists do include a boom retractable to within the cabin of the aircraft, however their configurations have generally proven to have various disadvantages. In one hoist of this type the hoist is mounted on a separate post extending from the floor to the cabin ceiling of the aircraft and includes a boom mounted on the post to pivot laterally about a vertical axis through the cabin doorway. In another known retractable hoist the boom is slidably supported on a railing through the cabin doorway. Both of these known retractable hoists are cumbersome because they tend to block entry into the cabin through the doorway and also because they use up valuable cabin space when retracted. A further disadvantage associated with these known retractable hoists is that they require an additional actuator to drive the boom between its retracted and deployed positions.
An object of the present invention is therefore to overcome the aforementioned problems and disadvantages encountered with known aircraft hoists.
A further object of the invention is to provide an aircraft hoist that avoids both engine inlet airflow distortion and aerodynamic drag increment during high speed flight.
Yet a further object of the invention is to provide a retractable hoist that uses less space, is easier to operate, is of less complex construction and is more reliable than known retractable hoists. In keeping with this object a more specific aim of the invention is to provide a hoist which requires only a single motor for powering both the boom extending and retracting function and the cable raising and lowering function of the hoist.
Other objects, features and advantages of the present invention will be readily apparent from the following detailed description and claims taken in conjunction with the accompanying drawings.